Shock absorber



' Sept 19, 1944 E. w. JoHNsoN A 2,358,714

' SHOCK ABSORBER Filed Sept. 18, 1942 2 Sheets-Sheet v1 i Inv-MP RN fww.

MCA 9454295;

sept. 19, 1944.

E. w.J`oHNsoN l 2,358,714

sHocx ABSORBER Filed Sept. 18. 1942 Sheets-Sheet 2 Patented Sept. 19, 1944 l SHOCK ABSYORBEB,V kErnest William Johnson, Birmingham, England, j `as signor Vof one-halfto Vandervell Products Limited, London, England, a British company Application September 18, 1942, Serial No. 458,878

In Great Britain October 8, 1941 according to circumstances.

'The inventionis concerned "with shock absrbersof thetype in which'a restricted passage for the owof `the dampngffluid is provided be? tween the opposed surfaces of a'perforation ina piston and va meteringlrod which reaches into said perforation insuch manner that the piston reciprocates -along'th'e metering rodinsi'de the shock absorber casing, and in which the metering rod has through its interior a by-pass for the said restricted passage. A shock absorber of this type is described in United States Patent No, 2,331,782. In this specification certain constructions are described l:in which a metering pin reaches into the interior ofthe metering rod to control the passage of -damping fluid throughthe Icy-passl The shock. absorberaccording to the present invention,also embodies a metering lpin of this general nature .but Vaccor-,ding :to the characteristic feature of thepr esent inventonthe metering vvpin vis a stationary tting detachably Y mounted insidefthe' shook absorber casing, Thus',

when itis desiredtochangethe character or shock-absorbing value of the shock absorber Athe stationary metering pin may be removed and ane other substituted .according to requirements. Any line adjustments required inthe shock-ab; sorbing value of the shockfabsorber'may thusbe simply effected by changing 'thelmet'ering pin.

conveniently, themeieringpin is foimedvwitn cwefpertionjs of different' diameters meng "its length, the larger of which portions is .a close'it in the housing for they pin, Vand the smaller of which portions issmaller than the by-pa'sspassage through themetering'rrod and 'reaches' into said by-pass passage toa position to 'control the mouth of a'conduit in the. metering rod which extends from the'byfpasspa'ssage to the exterior of the rod. The said larger'portion of the metering pin may be Vdirectly housed 4in the bore of the metering rod Land the pin beA detachableby sliding endwise when the is exposed. Y Y

For a more complete understanding of these end ofthe metering rod Y and other features of the invention there will Y now be described, bywayi of .example only and sorber `accordir'lgto'ftheinvention.` 'It is to be understood, howeventhatthe invention isv not tion shown in Figure l are as follows:7^

restricted to the precise constructional details set forth.

In these drawings: Figure 1 is a sectional 'elevation corresponding in most respects to Figure 1 of the drawings of the specification Serial No. 434,154. Y Figurel 2 is a detail sectional view of a modified constructionon a scale larger than that of Figure 1,l and j AFigure 3 is a view similar to Figure 2 of another modified construction.Y I Like reference numerals vindicate' like parts throughout the drawing. Referring firstly to AFigure l, itis notY necessary to 'describe herein the Whole of the details shown in this figure because, as already' indicated, many Vof them are already described in Patent jNo. 2,331g782. The main features of the' construc- Q The shock absorber comprisesa casing i5 with anupstanding centre barrel 'I6 having a cover plate' I1.' At the sidegythere are lugs I8 whereby the casing is mounted in place, and thebarrel i6 providesv bearings for` arockfshaft 2lV which is yconnected to one 0i the parts to be controlled by the shock absorber. The casingV l5 has bosses 26 and 21 which receive thefluidcontainer cylyir'iders 28 and 29 in which are pistons 3G and'3l which arereceived on ra sleeve 32 anda seal is made between each piston and the appropriate end of Vthe sleeve. Theouter ends of the cylinders'28 'and 29 have end caps 40 and 4I into both of which a metering rod 94 is screwed. The metering rod v94 lreaches right through the interior of the sleevey 32 andthe restricted passage throughwhich the damping fluid passes between the cylinders 28 and 29 lies between the opposed surfaces of the sleeve 32 and the meteringrqd 94. In'use, fluid will'be forced from thecylinder 28 to the-cylinder-29, and `in'u'zeversa along the said restricted passage as .the rock shaft 2l oscillates. The metering vrod 94 ishollow and near each end Ahas lateral conduits 95'estab1ishing communica- Figure 1 a stationary'metering-pin 5lwliieh`,`

towards its outer end, is'fa.' close'or'pushintin the boreof the rod' 94. l Towardsitsinner fend it lis reduced in diameter and `lies opposite to the mouth of the conduit 95. Thus the damping fluid has to pass around the reduced portion of the P11150 in order to reach the conduit 95, and by choosing a suitable diameter for this reduced portion of the metering pin, any desired metering action as applied to the damping fiuid travelling along the by-pass can be obtained. This metering action will apply not only toldamping fluid passing out of the by-pass passage but also to damping fluid passing into the by-pass passage.

By removing the cap 40, the end of the metering rod 94 is exposed and the pin 50 can then be removed by sliding endwise if it is desired'to replace it by another pin in order to vary the metering effect. It will be appreciated that the cap 4|! is arranged to prevent undesired endwise v movement of the pin 50 in the outward direction.

. of the pin 50 terminates in a'nut 54 which seats against the outer face of the cap 52, with an interposed washer, when the parts are assembled. Thus the metering pin 50 is helds'tationary in its proper operative position but it can readily be removed for exchange purposes without detaching the cap 52. f

The construction shown in Figure 3 is similar to that shown in Figure 2, exeptfthat an abutment or shoulder 55 is' 4formed in the interior of vTo prevent undesired movement inthe inward direction, the pin 50 is formed with a head 5| to seat against the end of the metering' in Figure 2, the me-v pin which reaches Vinto the interior of the metering rod to control the passage of damping fluid through the by-pass, and means for detachably mounting said stationary metering pin inside the shock absorber casing and for precluding endwise movement of theA metering pin after the parts have been assembled.

v2; In a shock absorber inY which fluid friction is employed'for damping, the combination of a casing embodying two fluid containers, a piston i reciprocable in one of said containers and having a perforation extending through it from end to end, a hollow metering rod which reaches into 1 the perforation in such manner that the piston lreciprocates along the metering rod, the opposed vsurfaces of which perforation and metering rod V provide between them a restricted passage connecting the said fiuid containers, through which the metering rod 94 in order to prevent undesired Serial No. 434,154.

In all of the constructions according to the present invention, the metering lpin 5IlV is stationary. That isto say, it does not move in operation after it has once been placed in positionf l f Q It isto be understood that the inventioriis'not restricted to the precise constructional details set forth:`

I claim:

1. Inga shock absorberin whichfluid friction is employed'for damping, the `combination of a casing` embodying two fluid containers, a piston reciprocable in one of said containersV and having a perforation extending through itfrom end to end, a hollow metering rod whichrreaches into x the perforation in suchmanner that the piston to the exterior of the rod,Y a stationary metering 75 passage the fluid is forced by the said piston, and the interior of which metering rod constitutes a by-pass for the said restricted passage, which hollowrmetering rod is formed with a lateral ccnduit extending through its Wall from the interior to the exterior of the rod near one end and with a housing at said end for a metering pin, a stationary metering pin to control the Passage of damping fluid through the by-pass, which pin is formed with two'portions of different diameters along its length, the larger of which is a close t in said housing and the smaller of which is smaller than the by-pass passage through the metering rod and reaches into said by-pass passage to a position'to control the mouth of the said lateral conduit, and means for detachably securing the metering pin in said housing and maintaining it against endwiseV movement after the parts have been assembled.

3. In a shock absorber in which fluid friction is employed for damping, the combination of a casing embodying two fluid containers, a piston reciprocable in one of said containers and having a perforation extending through it from end to end, a hollow metering rod which reaches into the perforation in such manner that the pistonreciprocates along the metering rod, the opposed surfaces of which perforation and meteringk rod provide between them a restricted passage connecting the said fluid containers, through which passage the vfluid is forced by the saidV piston, and the interior of which metering rod constitutes a by-passfor the said restricted passage,'which hollowmetering rodv is Vformed with'a lateralconduit extending through its wall from the interior to the exterior of the Vrod near one end, a stationary metering pin `to Acontrol the passage of damping fluid through. the bypass, which pin is'formed with two portions of different diameters along its length, the larger of which is a close't in the bore of the metering rod and the smaller of which is smaller than the by-pass passage through the metering rod,v

and means for detachably securing the meteringr Din in the endrof the metering rod in such manner that its smaller portion reaches into the by-pass passage to a position to control the mouth of the said lateral conduit, and that the reciprocates along the metering rod, the opposed surfaces of which perforation and metering rod provide between them a restricted passage connecting the said uid containers, through which passage the uid is forced by the said piston, and the interior of which metering rod constitutes a by-pass for the said restricted passage, which hollow metering rod is formed with a lateral conduit extending through its wall from the interior to the exterior of the rod, a stationary metering pin which reaches into the interior of theY metering rod to control the passage of damping uid through the by-pass, and a detachable end cap with a through screwthreaded bore into the inner end of which is screwed an end of the metering rod in such manner that the end cap seats against the shock absorber casing to secure the metering rod in position and into the outer end of which bore the head of the metering pin is screwed in such manner that the body of the metering pin reaches into the `bore of the metering rod to a position to control the mouth of the said lateral conduit.

5. In a shock absorber in which fluid friction is employed for damping, the combination of a casing embodying tWo uid containers, a piston reciprocable in one of said containers and having a perforation extending through it from end to end, a hollow metering rod which reaches into the perforation in such manner that the piston reciprocates along the metering rod, the opposed surfaces of which perforation and metering rod provide between them a restricted passage connecting thesaid fluid containers, through which passage the fluid is forced by the said piston,

and the interior lof which metering rod constitutes a by-pass for the said restricted passage,

Which hollow metering rod is formed with a lateral conduit extending through its wall from the interior to the exterior of the rod, a stationary metering pin which reaches into the interior of the metering rod to control the passage of damping fluid through the by-pass, and a detachable end cap with a through screwthreaded bore into the inner end of which is screwed an end of the metering rod in such manner that the end cap seats against the shock absorber casing to secure the metering rod in position and into the outer end of which bore the head of the metering pin is screwed in such manner that the body of the metering pin reaches into the bore of the metering rod to a position to control the mouth of the said lateral conduit and the outer end of which head on the metering pin affords a shoulder which seats against the outer face of the said cap when the parts are assembled.

ERNEST WILLIAM JOHNSON. 

